Siemens SINUMERIK 840D sl Function Manual page 150

B3: Several operator panels connected to several NCUs, distributed systems - only 840D sl
2.6 Link axes
Non-cyclic communication
● Exchange of link variables
● Warm restart requirements
● Activation of axis container rotation
● Changes in NCU global machine and setting data
● Activation of axial machine data for link axes
● Alarms
Transfer time
Delays are incurred for transferring setpoints to the home NCU of a link axis and for
returning the actual values of this axis. With an interpolation group of local axes and link
axes, the control delays the setpoints for the local axes of the interpolating NCU by one
interpolation cycle, such that consistent values are taken into account for the interpolation.
If a channel needs the actual values of an axis of another NCU, e.g. a spindle with thread
cutting, two interpolation cycles will elapse before they are available. The setpoints then
generated are sent one interpolation cycle later to the position control for the above reason.
Response of the AXIS-VAR server to errors
If the server cannot supply any values for an axis (e.g. because the axis concerned is a link
axis), then it returns a default value (generally 0).
For the purposes of testing, the machine data of the axis data servers below can be set to
sensitive, with the result that it returns an error message instead of default values:
MD11398 AXIS_VAR_SERVER_SENSITIVE
0: Default value
1: Error message
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Function Manual, 09/2009, 6FC5397-1BP20-0BA0
Extended Functions